Means for preventing pitching of ships



E. A. SPERRY MEANS FOR -PREYVENTING PITCHINGOF SHIPS April 14, 1931.

Filed April l5; 1927 Patented Apr. 14, 1931 RLMER A. sPERRY, OP BROOKLYN, NNW YORK',

COMPANY, OP BROOKLYN, NEW YORK, A CORPORATION ASSIGNOR TO THE SPERRYI GYROSCOVPE,

or NEW YORK 'MEANS POR PREVRN'PINGPITOHENG or SHIPS Application ined Api-i1 1s,

This invention relates to automatic means for lessening the` pitching of 'ships The prevention of rolling in ships has long been known and is. usually accomplished by a large gyroscopic' stabilizer which suppresses rolling by direct gyroscopic reaction. Such a means, however, ,isnot feasible for preventing pitching on account of the very much greater mass moment of the ship about itsaxis of pitch than about its rolling` axis. According to myfinvention, I propose to suppress pitching by locating small divingrudders near the bow of thev ship, and possibly alsol at the stern, and 'providing automatic means for turning or feathering theseV rudders in such a way that they' impose av counter pull of large magnitude whenever the bow is rising or falling. Means may also be provided for withdrawing the rudders flush with'the skin of the ship and also for.V varying the amount of feathering in accordance with the amplitude of pitch. lBoth of lthese features are impportant as they reduce the head resistance. to a minimum. Preferably the rudders or fins and also the operating mechanismk therefor are placed withinthe bulbous bowwhich is now provided on many large ships so that the head resistance of the ship is not increased. y

Referring to the drawings in which what I now consider the preferred form of myl invention is shown:

. Fig. 1^is a sectional elevation through the l bulbous bow of the ship'showing my invention mounted'therein.

. Fig.

2 is a front vertical, section taken just inside the bow of .thevship'as shown in Figli. v. jv

Fig. 3 is a horizontal section take'n'just below the roof ofthe water-tight compartment shown in Fig. 1. v Fig. 4 vis a detailedsectional view of a locking mechanism for vcentralizing the fins, before withdrawing the same into lthe bow'.y

1927. ,serialiy No. 183,275'.

Fig. 5 is a diagrammatic view ofthe side elevation of the ship showing the vlocati/on of my invention thereon. i

The rudders 1 and 1 v,are preferably balanced and protrude on V,each sidel of the bulbous bow 2 of theship. Long lrigid stems 3 and 4 protrude inboard from each' side of the'rudders and are secured in out-A board half or split (top and'bottom) journals 5V and full journals' 6. These heavy stems can rotate as Well as slip along in vthese bearingsY to withdraw the rudders. Rack barsl 7 and 7 and pinion sectors 8 and`9 serve to rotate the stems slightly and thus feather the'rudders 1 and 1 by the action of aservo motor, such as hydraulic cylinder 10.` 'One end of lever 11 moves with the rack 7 orpiston of cylinder 10, saidy lever being pivoted at its other kend 11 'I`heycylinderv 10 of controller such as theusual balanced piston valve 12 having a stem 13' operated by floating lever 14 pivoted on one end of link 2 1 by a vtransverse pin thereonwhich eX- tends through arcuateslot 22 in lever 14.

The other end of lever 14 is actuated by link 17 pivoted to the .arm 18 (Fig. 4) which isv pushes the levers of the scissors" freely on account of the valve against the spring26 of the dashpot 29 be- 27 in the plunger 28 ing open on the' down stroke. said valve and dashpot, the scissors `close slowly but open' freely. The position of the scissor arms determinesi the `position of thev is provided with some formV Also due tol link 21 in the groove 22 through the link 32, lever 65 pivoted at 66 and link 67 pivoted at one end to link 21 and at 16 to lever 65. As a gyroscopic baseline mechanism, I have shown at 33 a pneumatically damped gyroscopic pendulum which is maintained with` a high degree of accuracy regardless of the plane of the ship. The vertical fore and aft plane is the one selected for the position ofrack sector 3,4 on the gimbal 35 of the gyroseope, which is pivoted at 36 andV cooperates with pinion 37 driving contact wheel 38. The cooperating contactorv or trolley 39. is mounted on wheel 40, the axis of which is'V coincident with that of pinion 37 and which is driven from pinion 41 and ultimately from the follow-up motor 42. Pinion 41 also drives wheel 43 which carries the pin 24 on center 25 through an intermediate step down gears44, 44. The ratios are so chosen as to give the scissors 23 their maximum amplitude with the maximum amplitude of Apitch of the ship.

VThe operation of the scissors mechanism will thus be readily apparent. Each time the vessel pitches the follow-up motor 42 aetuates the. Pill 24 through the multiplying: gearing at a much more rapid rate than Vthe, ratey of displacement ofthe gyro with respect to the ship, The scissors open freely but Vclose slowly and hence, depending upon thevelocity of pitch, the said scissors will.

remain open fora longer or shorter period thus actuating the diving rudders for a longer or shorter period te counter-act the pitch. It will thus'be seenuthat` I utilise twov factors for controlling the counter-acting inovement'of the diving rudders. The first of these isthat due to the displacement of the gyro with respect to the shipwhen pitching occurs which operates link 17 ,and the secondof these is the opening of scissors 2 3 which 4depends upon the velocity of displacement. Both of these Vfactors control the dev gree of actuation of link 11and hence of the rudders4 I have, therefore, a system wherebyl move a plurality of divingrudders in a direction to counter-act pitching, the said movement vbeing a function of both the degree and the velocity of pitch.

y'Thev friction dnum 19 is'oonnectedV with the positively driven gear 40, which through the VfollQw-up is made te rotate with every; movement in elevation which constitutes the` pitch. The fellow-upv motor` 42 actsy in response to the trolley 3,9 and the reversing contacts; onl wheel 38in thefusual manner.' The foundation 3Q moves with,A the ship whereasthel gyro and rack 34 refuse to move but stand in space actuating the con-` tacts and instituting the positive ,follow-up motion. Vwhich is Used for reversing the. feather Oftllefluddee l and, l et each end oi the esellatonfley drum lalld te eentrlel the amount of feathering Vthrough 'the promptness and extent of action of the valve follow-up gear for valve 13 which is controlled by the pin 24 acting through scissors 23 and connection 32.

Describing now another secondary function, the withdrawing mechanism shown in Fig. 3, consists of bell crank levers 44 and 44, pivoted on the vertical stems 45, and geared together by gear sectors 61. Stems 45 passk up through the stuliing boxes 46 in wall 47 separatingy the waterl compartments below from lthe other parts of thel ship. The outer ends of said levers 44 and 44 Operate in jews 48 in. each` ef the stems 3f end4 end-n, swingnginte their inner position (shown in dotted lines) withdraw completely therudders 1 and 1 within the bulbous bow 2, the stems 3 and 4 sliding in their bearings as described. The hydraulic cylinder 49.. effects this Withdrawal, operating.v yagainst the compression spring 50 through the action of the valve 51' which is held'out of action by the circular `portion1 52, (also shown in Fig. 4), by slide 53 whichv leaSed. The object ofv pin 54 is Vto accuratelyV centralize the friction clamp 19l and lock the saine in its central position regardless of Vdrum 20., This meansthat the piston of cylinder vl() and racks 7 occupy their central positions andthat the rudderplates v1 will then just slip into tight fitting slots'56 in the skin of the ship into which `they may be quite well fitted thus lling the hole whichfexists when they are protruding and active. The cavity may thus be pumped out and entered for inspection, the pumps capacity being greater than the leaks.

ln Fig. 1 it will be seenthat the rudders are not in` the same horizontal plane. This is for securing the greatest length of anchorage between journals 5 and 6 in the interior of the bulbous bow so as to aid the rudders in withstanding the heavy pressures invelved. in their eeten The connection 21 connecting with lever 1 1 should also be suitably packed as by a wobbling bellows form of Apacking shown at 60, this giving freedom fory all its movethe gear so that the trolley will again be brought on to the insulated section 38. As gear 40 rotates, drum 2O is carried with it, thereby moving the slip-friction clamp 19 clockwise to carry the arm 18 against upper stop 18. The valve 12 is, therefore, moved downwardly to cause the piston in cylinder 10 to turn the rudders 1 and 1 counterclockwise to exert an upward torque on thev bow. 'Ihe extent of movement of the fins is governed by the prevailing amplitude of pitch through the scissors mechanism 23, the scissors being opened by the oscillation of the pin 24: which is driven from the gear 40 through reduction gearing an amount proportionate to the prevailing amplitude of pitch. As soon as the direction of pitching motion reverses, the feather of the rudders is reversed, for just as soon as the direction of pitch reverses the arm 18 is snapped against the lower stop 18, thus reversing the valve 12. While I employ, therefore, a gyro pendulum having three degrees of freedom for controlling the rudders, the reversal of the feathering does not wait until the ship passes through its level position but takes place as soon as the direction of the pitch of the ship takes place.

In case calm weather is encountered, the ns may be withdrawn by turning the valve 51. This valve can only be turned as explained when the fins are in line with the slots 56, the locking mechanism 52, 53 and 54 lining up the fins before the valve 51 can be turned.

In accordance with the provisions of the patent statutes, I have herein described the principle and operation of my invention, to-

i gether with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of and others omitted without interfering with the more general results outlined, and the invention extends to such use.

` Having described my invention, what I claim and desire to secure by Letters Patent is:

1. The combination with a ship having a bulbous bow, of a water-tight compartment i in said bow, a pair of fins rotatably mounted in said compartment and extending without the bow on each side, and means for feathering said fins also mounted within said bulbous bow and said compartment.

2. The lcombination with a ship having a bulbous bow, of a water-tight compartment in said bow, a pair of fins rotatably mounted in said compartment and the bow on each side, means for feathering said fins, and means for withdrawing said extending without f fins within said compartment when'not in se. n 4 3.' Av stabilizer forfreducing the pitching of ships comprising a pair of feathering'diving rudders, a gyroscopic'pendulum, pitchresponsive means adapted to be reversed upon `reversal of direction of pitch, 'and means actuated by said responsive means upon a vchange in the direction of pitch of the ship with respect to said gyroscope for reversing the feather of the rudders toI oppose the pitching motion.

, 1. A stabilizer for vreducing the pitching of ships comprising a pair of feathering diving rudders, a gyroscopic pendulum, pitch-responsive means adapted to be reversed upon reversal of direction of pitch, means actuated by said responsive means upon a change in the direction of pitch of the ship with respect to said gyroscope for reversing the feather of the rudders to oppose the pitching motion, and means responsive tothe amplitude of pitch for governing the amount of feathering.

5. rIhe combination with a ship having a bulbous bow, of a pair of fins rotatably mounted therein and extending without the bow on each side, means for-feathering said fins, means for withdrawing said fins within said bulbous bow through slots infsaidl bow, and interlocking means for yaligning said lins and slots before they can be moved Ainwardly. y

6. A stabilizer for ships including a gyro-pendulum, contacts displaceable by relative movement of said gyroscope and ship, a follow-up motor driven therefrom, aslip- `friction device Voscillated by changes in the `direction of rotation of said motor, feathering rudders for stabilizing Vthe ship, a servo- 'motor for actuating the same, and a controller therefor actuated from said slip-friction connection.

, 7. A. stabilizer for ships including a gyropendulum, contacts displaceable by relative movement'of said gyroscope and ship, a follow-up motorvdriven therefrom, a slip-friction device oscillated by changes in the directionof rotation'of said motor, feathering rudders for stabilizing the ship, a Lservo-motor for actuating the same, a controller therefor actuated from said slip-friction connection, and means actuated `by the extent of rotation of said follow-up motor and operating on the connections between said device and said servo-motor for varying the motion imparted to said controller for the purpose v specified.

' limones,

Water-tight compartment. enclosingportions of both of said means.

9.' A stabilizer for reducing the pitch of ships, comprising a plurality of featheringl 5 diving rudders, means responsiveto the degree of pitch, means responsive to the velocity of pitch, means for eathering said rudders to oppose the pitching movements, and means whereby said last-named means is con- 10 trolled jointly by said rst tWo means.

In testimony whereof I have aiiiXed my signature.

' ELMER A. SPERRY. 

